Improvement in lathe-chucks



To all whom it may concern:

State of Connecticut, have invented certain FFIGE.

FRANK'ARMSTRONG, OF BRIDGEPORT, CONNECTICUT. I

IMPROVEMENT IN LATHE-CHUCKS.

Specification forming part of Letters Patent No. 189,188, dated April 3, 1877; application filed February 28, 1877.

Be it known that I, FRANK ARMSTRONG, of Bridgeport, in the county of Fairfield and new and useful Improvements in Lathe- Ohucks and I do hereby declare that the following is a full and exact description thereof, reference being bad to the accompanying drawing, making a part of this specification.

My invention relates to certain improvements in lathe-chucks, such as are fully shown and described in Letters Patent No. 154,162, dated August 18, 1874.

My invention has for its object to prevent any unevenness ot' wear'incidental to the frictional contact between the central bevel-gear and itscontaining-shell; and consists in forming the rear supporting portion of the shell with a beveled face, and the gear with a cor respondingly-shaped face, so that any wear taking place will not affect the axial relation of the parts, as will be hereinafter more fully set forth.

In the accompanyingdrawing I have represented a central longitudinal section of only so much of such a chuck .as is shown in the patent herein before referred to as is necessary to illustrate the feature of my invention.

A represents the rear half-shell, which incloses the central bevel-gear B, which are held in contact by means of a nut, O, and washer D. Those portions of the gear B and shell A which arein frictional contact are beveled towardthe axis of the gear, as clearly shown in the drawing, and as all wear taking place is concentric with the axisof the gear, it follows that the axial relation between the gear and shell is always maintained.

I am aware that it is not new to return the shell A and form therein an annular V-shaped groove adapted to receive a corresponding V-shaped rib on contact-face of the gear, nor do I wish to layclaim thereto but What I claim as new, and desire to secure 

